Spatial and temporal expression of RA70/Scap2 in the developing neural tube

Src kinase-associated phosphoprotein 2 (Ra70/scap2), which was originally isolated as a retinoic acid (RA)-induced gene, associates with molecules that modulate integrin-survival signals. Although RA is essential for vertebrate organogenesis in the posterior region, little is known about the biological role of RA70/Scap2 during development. In the present study, we demonstrate that Ra70/scap2 mRNA is temporally expressed during the RA-induced neuronal differentiation of P19 embryonic carcinoma cells. Homozygous knockout mice in which the Ra70/scap2 gene was replaced with LacZ exhibited embryonic lethality, while heterozygous mice displayed preferential expression of LacZ in posterior neural tissues, including the neural tube and hindbrain during development (E7.5-11.5), but not the forebrain. Ra70/scap2 was expressed in the ependymal layer and ventricular zone in the neural tube, where neuroepithelial cells and neuroblasts with proliferation capacity are localized, respectively. Thus, RA70/Scap2 may be necessary for RA-induced neuronal differentiation from the posterior neuroectoderm.